Definitions for "contract size"
Keywords:  underlying, shar, tonnes, split, parity
The quantity of the underlying security that the holder of an option possesses...
The number of units of an underlying specified in a contract. In stock options the standard contract size is 100 shares of stock. In futures options the contract size is one futures contract. In index options the contract size is an amount of cash equal to parity times the multiplier. In the case of currency options it varies.
The amount of the underlying asset which one futures contract represents, e.g. the contract size for a copper contract is 25 tonnes. This means that underlying one copper future is 25 tonnes of copper which the investor has the obligation to buy ( long future) or sell ( short future).
The actual amount of a commodity represented in a contract.